Advice about brother

Hiii I’m just really worried about my younger brother.

He smokes a lot of weed and I’m just scared it could be laced with something and he becomes addicted to drugs.

Not only that but he keeps bringing this like gel in the house which I’m not even sure what type of drug it is.

He plays an unhealthy amount of video games and has no drive at all or any confidence.

I just don’t know what to do or why he’s struggling. I asked my parents if maybe he could see a counselor or something. He doesn’t really talk to us and I can tell he’s depressed.

I just don’t want anything to happen to him ever and it’s so sad to see him like this